Tracing overlapping biological signals in mid-infrared using colonic tissues as a model system

Figure 5 Extrapolation of the principle/observations to disease conditions. A: Difference spectra between normal, IBD (Crohn's-H and Ulcerative colitis-UC) and cancer (C) tissues showing similar pattern to the difference spectra obtained by subtracting normalized spectra with apertures 120 and 90 μm (bold black line); B: Second derivative of the difference spectra of 120 and 90 μm showing peaks corresponding to nucleic acid absorbance (DNA-1020, 1080, 964). The difference spectra of IBD, normal and Crohn’s represent the average spectra for each category from ten different patients subtracted from the average normal spectra.